The present invention relates to vehicle suspension systems, and more particularly, to an automotive suspension system in which a composite elongate member functions as both a control arm and a spring to thereby reduce the weight and number of part otherwise required.
Vehicle suspension systems have heretofore included shock absorbers, springs (coil, leaf, air or torsion bar), axle housings, torque arms, A-frames, anti-roll bars, stabilizers, and so forth. These components have been assembled in various combinations to produce the desired ride and handling characteristics of the vehicle. In a typical suspension system, changes in the spacing between axles and the body/chassis are cushioned by springs, Spring vibration is limited by dampers which are usually called shock absorbers. The shock absorbers dissipate the energy stored in the springs by gradually forcing oil through orifices and valves. The flow resistance encountered by the oils results in compression and rebound forces which control the spring movement. The work done by the oils as it moves through the valves converts energy stored in the springs into heat which is dissipated from the shock absorbers into the surrounding air.
There is a continuing effort to reduce the manufacturing cost of automobiles. There is also a continuing effort to increase the mileage of automobiles through weight reduction. Both of the aforementioned efforts must not unduly sacrifice performance or reliability. Conventional suspension systems tend to have numerous expensive heavy metal parts. It would be desirable to reduce the cost, weight and complexity of existing suspension systems.
U.S. Pat. Nos. 1,679,853 of Cottin; 2,126,130 of Nallinger; 2,157,773 of Probst; 2,177,897 of Lee; and 2,697,613 of Giacosa disclose various automobile suspension systems utilizing transverse leaf springs. Canadian Patent No. 954,149 discloses a fiber reinforced composite leaf spring. U.S. Pat. No. 4,557,500 discloses an automobile suspension system utilizing a transverse composite leaf spring. The leaf spring is mounted to the chassis on opposite sides thereof.
U.S. Pat. No. 2,635,894 discloses a lower control arm 9 forming one leg of a relatively thin and wide L-shaped plate 10 of spring steel or "equivalent elastically flexible material." The portion of the plate inside the frame serves as a torsion spring and not the arm 9 itself.
French Patent No. 2,528,364 discloses twin fiberglass trailing arms for rear wheel suspension. The fiberglass arms can have two layers.